1. Field of Invention
The invention relates to a valve for vacuum handling devices or vacuum clamping devices, having a valve housing which has a suction side and a vacuum supply side for connection to a vacuum supply device, a flexible dividing wall which delimits a control space in the valve housing, which control space is connected to the vacuum supply side via a vacuum passage, and a valve body which is arranged on the flexible dividing wall and can be moved between an open position and a closed position, wherein the valve body has a sealing portion which seals off the vacuum passage in the closed position and which opens up the vacuum passage in the open position, and wherein, based on a vacuum that develops in the control space, the volume of the control space is reduced with a deformation of the flexible dividing wall, and the valve body is moved from the open position into the closed position, so that when suction is freely applied while the suction side is unoccupied, the valve body can be moved to the closed position as a result of a vacuum that develops in the control space, wherein the valve body has a suction-side passage for connecting the suction side to the control space in terms of flow. This type of valve closes automatically when a suction point is unoccupied, thereby preventing undesirable leakage from the suction side of the valve to the vacuum supply side.
2. Description of Related Art
Various solutions for preventing undesirable leakage when the suction point is unoccupied are known. For example, DE 34 29 444 A1 discloses a flow valve in which a valve element embodied as a ball is displaceably situated in a flow channel. When suction is freely applied through the unoccupied suction point, the strong flow impulse carries the ball along in the flow channel and up to a valve seat, thereby sealing the flow channel. Because they are activated by flow impulse, valves of this type are prone to malfunction as a result of flow bursts. Even when the suction point is occupied, the valve may close unintentionally at the start of a suctioning process as a result of the initial flow burst.
Also known are valves that close automatically when the suction side is unoccupied not as a result of a flow impulse, but as a result of a static pressure difference that develops under free suction. DE 198 14 262 C2 discloses a valve having a valve housing which has a suction side and a vacuum supply side for connection to a vacuum supply device, a flexible dividing wall which delimits a control space in the valve housing, which control space is connected to the vacuum supply side via a vacuum passage, and a valve body which is arranged on the flexible dividing wall and can be moved between an open position and a closed position, wherein the valve body has a sealing portion which seals off the vacuum passage in the closed position and which opens up the vacuum passage in the open position, and wherein, based on a vacuum that develops in the control space, the volume of the control space is reduced with a deformation of the flexible dividing wall, and the valve body is moved from the open position into the closed position, so that when suction is freely applied while the suction side is unoccupied, the valve body can be moved to the closed position as a result of a vacuum that develops in the control space, wherein the valve body has a suction-side passage for connecting the suction side to the control space in terms of flow. The control space, which is delimited by a flexible portion of the valve body, is in constant connection with the vacuum supply side. When the control space is compressed, the flexible portion is deformed, moving the valve body to its closed position. The control space is completely sealed off from the suction side in terms of flow. When suction is applied while the suction side is occupied, a vacuum will not develop on the suction side. This causes the control space to become compressed as a result of the static pressure difference between control space and suction side, thereby moving the valve body into its closed position. This valve has the advantage over valves that function by means of flow impulse that malfunctions resulting from flow bursts can be prevented. However, the time scale for automatic closure and the sensitivity to pressure fluctuations must be adjusted for the specific vacuum handling device or vacuum clamping device that is controlled by the valve.
DE 102 16 220 A1 discloses a vacuum pressure valve having a valve housing with a suction side and a vacuum supply side for connection to a vacuum supply device, a flexible dividing wall which delimits a control space in the valve housing, which control space is connected to the vacuum supply side via a vacuum passage, and a valve body which is arranged on the flexible dividing wall and can be moved between an open position and a closed position, wherein the valve body has a sealing portion which seals off the vacuum passage in the closed position and which opens up the vacuum passage in the open position, and wherein, based on a vacuum that develops in the control space, the volume of the control space is reduced with a deformation of the flexible dividing wall, and the valve body is moved from the open position into the closed position, so that when suction is freely applied while the suction side is unoccupied, the valve body can be moved to the closed position as a result of a vacuum that develops in the control space, wherein the valve body has a suction-side passage for connecting the suction side to the control space in terms of flow, in which the valve body is formed by a disk-like element.